Among Tianjin’s legendary culinary treasures – alongside Goubuli buns, Guifaxiang dough twists, and Erduoyan fried cakes – there is a vegetarian delight that has quietly fed the city for over a century. Its name, Shitou Menkan (石头门坎), means “Stone Threshold” – and behind it lies a tale of flooding, fortune, and an empress’s favour.…